Method and apparatus for the treatment of domestic waste

ABSTRACT

Method of treatment of domestic waste. A reaction space is provided, into which the waste to be treated is fed at a controlled rate. The waste is concurrently compacted to form a stopper preventing leakage of gases from the reaction space. An oxygen-containing gas is fed to the reaction space, in order to affect the combustion of the waste and produce gases and solid material. The gas is filtered through the solid material, causing the gases to react with the solid material, whereby to produce fuel gases and ash.

FIELD OF THE INVENTION

This invention relates to a method and apparatus for the treatment ofdomestic waste, for the purpose of disposing of it in an ecologicallysound manner and producing from it combustible gases, particularlycarbon monoxide and hydrogen.

BACKGROUND OF THE INVENTION

The ecological disposal of domestic waste and the production of usefulproducts, specifically combustion gases from it, form the subject matterof a number of proposals in the prior art.

Domestic waste is usually treated after having been accumulated asmunicipal waste. Its composition is highly variable. It is oftenreferred to as “biomass”, since it contains a considerable proportion offood residues, but in reality it is only partially a biomass. It may,and frequently does, also contain considerable amounts of cardboard andpaper and generally cellulosic material or partly cellulosic materialsuch as wood. It also does contain inorganic materials, such as metal orglass or even rocks or sand, and other materials such as plastics,fabrics, and so on. As a result, part of the waste can producecombustible gases and an oxidation residue and part remainssubstantially unchanged, so that, at the end of any disposal andutilization process, a substantially inorganic ash is produced. Allpossible compositions of domestic waste can be treated by the method andapparatus of this invention, which is therefore not limited to any rangeof compositions and the term “domestic waste” is intended herein toinclude all compositions, but of course the parameters of the processmust be controlled to take into consideration the composition beingtreated. This, however, comes within the capabilities of skilled personsand requires no particular description, although some indication will begiven later.

EP-A 136 277 A2 discloses an apparatus and method for gasifying what iscalled “biomass fuels”. A mass refractory layer has a first inclinedfuel supporting ramp. A mass of refractory is provided opposing surfaceto define a primary gasification chamber. The chamber is sealed byanother mass of refractory. Biomass fluid, heated by radiation from therefractory, carbonizes and releases volatile gases. Additionally, theapparatus comprises a lower refractory layer having a second inclinedramp, which has a plurality of inlet holes to provide air distributionin a specific combustion zone located below the zone in whichcarbonization occurs.

WO 96/00267 discloses a process in which waste is charged into areactor, an oxygen-containing gas is injected into it, solid productsand gaseous products produced by the treatment are withdrawn, and thetreatment results from the successive passage of the waste through aheating and drying zone, a thermolysis zone, an oxidation zone and acooling zone. In this application the control of the temperature tomaintain it between 700 and 1400° C. is effected by controlling at leastone of the parameters among the oxygen mass fraction and the massfractions of the incombustible and the combustible components of thewaste.

WO 99/37738 (some of the inventors thereof are the same as those of thepreceding application) discloses a method of processing municipalwastes, primarily highly humid ones, which comprises drying, pyrolyzingand gasifying the waste by means of an oxygen-containing gas, attemperatures between 800 and 1300° C., by controlling the sameparameters as are controlled in WO 96/00267, with the feature that thesmoke gas, preferably a mixture with air, is used as the gasifying agentand the mass fractions of oxygen in said agent and of incombustible andcombustible components in the waste satisfy a certain quantitativecondition.

WO 99/42540 discloses a process for the gasification of biomass orbiomass-comprising materials, which gasification takes place in areverse-flow reactor in which the line of direction in which gas ispassed through the biomass cuts the line of direction in which thebiomass is supplied.

Japanese Application No. 07324432 discloses a burner for municipalrefuse, wherein the temperature of the burning space of the burnerchamber is raised to about 2000° C., then air is supplied and thetemperature of the uppermost layer of a fuel packed bed is raised.

Japanese Application No. 10153892 discloses a gasification furnace formunicipal waste divided by a partition plate into a first-stagegasification chamber for pre-heating and drying and a second-stagegasification chamber for obtaining partly oxidized gas.

The aforesaid and other prior art patents are not satisfactory for anefficient treatment of municipal wastes, for various reasons. Some ofthem do not permit continuous operation, or, if they permit it, it isvery difficult to control it. The efficiency of their processes islimited. The structure and the operation of the reactors are complicatedand expensive. Gas leakage problems are not considered, or ifconsidered, are not adequately solved. The waste must be sortedaccording to composition and dimensions of particles before recycling.

This invention therefore has the purpose of providing a method andapparatus for the disposal of domestic wastes and the production of fuelgas from it that are free of the defects of the prior art methods andapparatus.

Another purpose of the invention is to provide such a method andapparatus that are adapted to continuous production.

A further purpose is to provide such method and apparatus that permitcontrol of the feed of waste and of the rate of production in a full andadequate manner.

A still further purpose is to provide such a method and apparatus thatare reliable in operation.

A still further purpose is to provide such a method and apparatus thatare simple and economically convenient.

A still further purpose is to provide such a method and apparatus thatprepares insert and metal materials for use.

Other purposes and advantages of the invention will appear as thedescription proceeds.

SUMMARY OF THE INVENTION

The method of the invention comprises;

a) providing a reaction space including a first, incomplete combustionzone, and a second, gasification zone;

b) feeding the waste to be treated to said reaction space at acontrolled rate;

c) concurrently compacting said waste to form a stopper preventingleakage of gases from said reaction space;

d) feeding an oxygen-containing gas, preferably air, at a hightemperature and under pressure to said incomplete combustion zone,whereby to effect incomplete combustion n of said waste; and

e) filtering the gases produced by said incomplete combustion throughthe solid material in the gasification zone, whereby to produce carbonmonoxide and hydrogen.

In the incomplete combustion zone, besides the incomplete combustion ofthe waste, other phenomena may occur, including drying of the waste,evaporation of the water contained therein, and combustion of gasesproduced by the combustion of the waste.

The incomplete combustion of the waste will be called hereinafter“thermolysis” and the incomplete combustion zone will be calledhereinafter “thermolysis zone”. In said zone there are produced carbondioxide and a carbon-containing solid residue. The carbon contained insaid residue reacts with carbon dioxide and water according to the wellknown reactions CO₂+C=2CO and H₂O+C=H₂+CO.

The method of the invention also includes disposing of the ash that isthe final product of the gasification. It may also include controllingthe temperature in various parts of the reaction space by controllingthe temperature of the oxygen-containing gas fed thereto, controllingthe rate of feed of the waste and the resulting ratio of the waste feedto the oxygen-containing gas feed, and thermally insulating the reactionspace. All the amounts of materials will be expressed herein as weight,unless otherwise specified. Persons skilled in the art may carry outother temperature-controlling operations that are conventional inthemselves. Since the oxygen-containing gas is generally air,hereinafter reference will be made only to air for purposes ofdescription, but this does not involve any limitation of the invention.

The regulation of the process is a function of the composition of thegas produced (e.g., according to the equilibrium constant) and thetemperature of the reaction space. The regulation is effected bychanging the waste feed rate and the amount of air supplied.

The invention further comprises an apparatus which includes:

A. a reaction chamber, which comprises a thermolysis zone and agasification zone;

B. a feed vessel, hereinafter called “hopper”—in which term everypossible shape and structure thereof is intended to be included—intowhich the waste to be processed is loaded;

C. waste feed means for advancing the waste from said hopper to saidreaction chamber at a controlled rate and for compacting itconcurrently;

D. at least two conduits for the waste advanced by said hopper, set atan angle—preferably a right angle—to one another;

E. an air chamber in communication with said reaction chamber;

F. a gas-receiving chamber for receiving the gases produced in thegasification zone of said reaction chamber, provided with an outlet forsaid gases; and

G. means for discharging the ash formed in said gasification chamber.

In a number of embodiments, the apparatus further comprises a coolingjacket surrounding the upper portion of said reaction chamber, while thegas-receiving chamber surrounds the lower portion of said reactionchamber. In another embodiment, the air chamber and the gas receivingchamber together surround the reaction chamber.

The waste feed means for advancing the waste from said hopper to saidreaction chamber at a controlled rate and for compacting itconcurrently, preferably consist of two pistons, coupled to two wasteconduits. Since said conduits are at an angle to one another, generallyat a right angle, the waste advanced by the first piston will reach theend of the first conduit and be stopped by the wall of the secondconduit, whereby to form a stopper due to the pressure exerted by thefirst piston, said stopper being later advanced by the second pistoninto the said second conduit until it is discharged into the reactionchamber. The two pistons will be synchronized to carry out thisoperation, as will be explained hereinafter. While the aforesaidstructure of the waste feed means is preferred, it is not limiting, andother mechanical arrangements can be devised by skilled persons withinthe scope of the invention

The apparatus of the invention further comprises, or is associated with,means for feeding the air under pressure to the air chamber. Thatpressure drives the gases throughout the apparatus, and particularlydrives the combustion gases through the solid residue caused by thethermolysis of the waste.

The means for discharging the ash may be of any convenient mechanicalstructure, but preferably are similar to the aforesaid feed means, andcomprise a piston, a conduit for the ash advanced by the piston, and anoutlet.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic vertical cross-section of the apparatus accordingto an embodiment of the invention, taken on the plan passing through theaxis of the reaction chamber;

FIG. 2 is a schematic view of the apparatus of FIG. 1 from above,portions of the top plate thereof broken off to show the underlyingparts;

FIGS. 3A, B and C schematically illustrate various stages of the feed ofwaste material in the apparatus of FIG. 1;

FIG. 4 is a schematic cross-section at an enlarged scale of thethermolysis and gasification portion of the apparatus of FIG. 1 betterillustrating its operation;

FIG. 5 is a schematic vertical cross-section similar to FIG. 1, butillustrating a second embodiment of the invention;

FIG. 6 is a schematic cross-section of the reaction chamber of FIG. 5taken on plane VI—VI of FIG. 5;

FIG. 7 illustrates the apparatus of FIGS. 5 and 6 in operation;

FIG. 8 is a partial vertical cross-section of an apparatus according toa third embodiment of the invention;

FIG. 9 is a schematic cross-section of the reaction chamber of FIG. 8taken on plane IX—IX looking in the direction of the arrows.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference now to FIGS. 1 and 2, numeral 10 generally indicates theouter wall of the cooling and the gas-receiving chambers. The apparatusalso comprises a top plate 11 and a partition plate 12 which define theair chamber 13, said air chamber being provided with an inlet 14 for thehot air. Apertures 15, which in this embodiment are generallyhopper-shaped, having a broader upper portion and a narrower lowportion, provide communication between said air chamber 13 and a coolingjacket 16 in which cooling air is circulated through outlet 17 and inlet18. The cooling of the thermolysis zone is especially necessary at themoment of heating, because highly energetic fuel burns at temperaturesof 1200° C. and higher. Since when the operation of the apparatusstarts, the waste to be treated must be heated from the outside until acorrect operating temperature, preferably not more than 100° C., isreached, a hot gas may be temporarily circulated through jacket 16instead of cooling air, or electrical or jacket means may be sotemporarily employed.

A partition 19 separates cooling jacket 16 from a gas receiving chamber20 provided with outlet 21. A reaction chamber 22 is located below plate12 and centrally of cooling jacket 16 and of gas receiving chamber 20.The upper part of said reaction chamber is a thermolysis zone and thelower part is a gasification zone, but it should be understood that noprecise border between said two zones exists or can be established.Actually, during the operation of the apparatus, the zone in whichthermolysis ends and gasification begins may shift towards the top orthe bottom.

The means for feeding the waste to be treated to the reaction chambercomprise a hopper 23 for receiving the waste 29. Hopper 23 is coupled toa first conduit 24 (see FIGS. 3A, B and C) and discharges the waste intoit. A piston 25, only schematically indicated in FIGS. 1 and 2, is shownin three successive positions indicated as 25 a, 25 b and 25C in FIGS.3A, B and C. Piston 25 is initially in inactive position 25 a, butadvances to position 25 b in conduit 24 when waste 38 has beendischarged into conduit 24. It is then advanced to position 25 c, belowhopper 23 (see FIG. 3B), thus driving the waste along conduit 24 towardsa second conduit 26 disposed at right angle to conduit 24. As the wastereaches the junction 35 of the two conduits (see FIG. 2) its progressparallel to conduit 24 is stopped by the wall of conduit 26 and thewaste is compacted there and forms a stopper 36. A piston 27, onlyschematically shown in FIG. 2, is shown in two successive positionsindicated as 27 a and 27 b in FIGS. 3A, B and C. Piston 27 is initiallyin inactive position 27 a higher than conduit 24 (see FIG. 3B), butadvances to position 27 b in conduit 26 (see FIGS. 3A and C) after waste38 has been compacted into conduit 26 to form stopper 36. In so doing,it drives said compacted waste—said stopper—along conduit 26 until itreaches opening 28 (see FIGS. 1 and 4), viz. the outlet of conduit 26 inthe reaction chamber 22. Concurrently, piston 25 retracts to position 25b, to permit further waste to be discharged from hopper 23 into conduit24 (see FIGS. 3A and C).

FIGS. 3A, B and C also illustrates what happens to any solid pieces ofwaste, such as that indicated at 37. Said piece it is discharged fromhopper 23 into conduit 24 (see FIG. 3A). When piston 25 advances toposition 25 c, it may cut said piece into two fragments 37′ and 37″, oneof which (37′) becomes part of stopper 36 and proceeds to the reactionchamber, while the other fragments (37″) is pushed back into hopper 23,and may be further fragmented in successive strokes of piston 25.

The operation of the device requires synchronization between the pistons25 and 27, as illustrated in FIGS. 3A, B and C. For clarity's sake, thestroke of piston 25 from position 25 b to position 25 c, towards conduit26, will be called the forward stroke, and its opposite stroke will becalled the rearward stroke; and the stroke of piston 27 from position 27a to position 27 b, towards reaction chamber 22, will be called theforward stroke, and its opposite stroke will be called the rearwardstroke. When piston 25 is withdrawn away from the junction 35 ofconduits 24 and 26, hopper 23 can discharge its contents into conduit24. Concurrently piston 27 can advance to its position closest toreaction chamber 22 and drive the stopper, which has been previouslyformed at junction 35, towards said reaction chamber. Thereafter piston27 will effect its rearward stroke and leave junction 35 free to receivethe waste and concurrently piston 25 will effect its forward stroke,drive more waste to junction 35 and compress it there to form a new ash.Briefly it may be said that the synchronization is such that when one ofthe piston effects its forward stroke, the other piston effects itsrearward stroke, and vice versa.

It will be clear that, though the pistons have an alternating motion andthe waste is fed by portions, each portion being what was called a“stopper”, the operation of the apparatus is continuous for allpractical purposes, as the portions can be made small enough and thefrequency of the piston motion high enough, so that no overalldiscontinuity is felt. Additionally, as has been said, pistons 25 and27, and similarly pistons 25 and 41 or 52 and 54, can fragment and/orcut off parts which can disturb the movement of the waste in theapparatus, viz., it may be said, can act as guillotines. In this sensethe method and apparatus of the invention are said to be continuous. Ofcourse, they could be made absolutely continuous by using other wastedriving apparatus, e.g. of the screw extruder type, and skilled personscould easily substitute such apparatus for the one of the describedembodiment.

It will be understood that the waste does not progress freely in adownwardly direction because of its weight. It is continuously driven byincoming waste and remains substantially compacted. The reaction chambertapers towards the bottom, in frusto-conical shape, as seen in FIGS. 1and 4, and this taper is such that the waste and the carbon-containingsolid residues produced by thermolysis remain compact.

The thermal treatment of the waste is better illustrated in FIG. 4. Theupper part of the reaction chamber 22 is a thermolysis zone 40 and thelower part is a gasification zone 41. The two zones are not physicallyseparated and their borderline, indicated in broken line in FIG. 4, mayshift as the apparatus operates. The solid waste 38 enters thethermolysis zone from opening 28 of conduit 26. Air is fed from the top,through conduit 14, into a space between plates 11 and 12 and flowsthrough openings 15 into the thermolysis zone. It then flows downwardsthrough the waste and reacts with it, forming the fuel gases that arethe final product and that flow out through outlet 21.

The reaction chamber 22 has a lowermost portion 29 which tapers from topto bottom and is preferably frusto-conically shaped, as seen in FIGS. 1to 7. The lower opening 30 of reaction chamber 22 is located slightlyabove said portion 29. The ash formed in the gasification chamber isdischarged into said portion 29 and from there into a conduit 31 I(seeFIG. 2). Said conduit 31 is coupled with a piston 32 which drives theash towards an outlet 33.

In FIGS. 5, 6 and 7 the parts that are identical or similar to parts ofFIGS. 1 to 4 are indicated by the same numerals. The embodiment of FIGS.5, 6 and 7 firstly differs from the previously described embodiment inthat a pipe 40, corresponding in its function to pipe 26 of FIG. 2, ispositioned vertically, viz. a vertical plane and substantiallyperpendicular to feed pipe 24 and passes through a central opening ofplate 12. A piston 41 which has the same function as piston 25 of FIG. 2is actuated within pipe 40 between an upper position 41′ (indicated inbroken lines) and a lower position 41″. A stopper of waste forms at thejunction 42 of pipes 24 and 40, for the same reason and in the same wayas it was formed at the junction 35 in the previous embodiment.

The embodiment of FIGS. 5 to 7 also differs from that of FIGS. 1 to 4 inthat the reaction chamber, generally indicated at 45, has a rectangularcross-section, as shown in FIG. 6.

In the embodiment of FIGS. 8 and 9, the feed of the waste occurs throughhopper 50 and pipe 51 (said hopper and pipe actually merge into a singlestructure) and piston 52. The waste is fed to a pipe 53 in which isdisplaceable a piston 54. The piston 52 compacts the waste when thiscomes into contact with the wall of pipe 53 and forms a stopper. Piston54 is vertically displaceable and in its downward stroke, pushes thestopper of waste into the reaction chamber which is generally indicatedat 56. In FIG. 8, piston 54 is shown in its lowermost position and thereis no waste in pipe 53, while the hopper has been refilled of waste. Thefunctional relationship between piston 52 and piston 54 is the same asthat between piston 25 and piston 27 in the embodiment of FIGS. 1 to 4.So far, the present embodiment does not differ substantially from theembodiment of FIGS. 5 to 7. In this embodiment the reaction chamber 56is curved. Its axis is preferably an arc of circle, having a radius thatdepends on the properties of the waste treated and on the capacity ofthe apparatus. For example, for a waste gasification apparatus with thecacapcity of 0.6 ton/hr, the radius is in the range 2.1 to 2.8 meters.and subtending an arc of approximately 60 degrees. The reaction chamberhas an upper section 56′ which is circumferentially limited by wall 58having a circular cross-section and which extends to about one-half ofthe longitudinal, arcuate development of the reaction chamber. Below thewall 58, the reaction chamber has a lower section 56″, which isuncovered at its concave side, while at its convex side it is limited bya wall having perforations 55. The perforated wall covers from 27 to 33degrees. The sections 56′ and 56″ of the reaction chamber are notphysically separated and the passage from the one to the other changeswith variations in the process parameters and, in each case, with time,so that it is not possible to mark a separating line in FIG. 8. An airconduit 60 surrounds the reaction chamber on its concave side and hasthe same cross-sectional, angular development as the uncovered portionof the reaction chamber section 56″. It receives air from opening 61, atany suitable pressure, and the air is ejected through perforations 62,so as to form between the conduit 60 and the reaction chamber an airchamber 63. On the convex side of the reaction chamber, a gas settlingchamber 64 is formed, which tapers into a gas conduit 65 terminating ina gas outlet 66, from which issue the fuel gases produced, which arethen collected and utilized in any convenient manner, not illustrated.At the lowermost portion of the reaction chamber, the spent wasteaccumulates into a conduit 67. A piston 68 pushes the spent waste intosaid conduit, from which it is ejected by a piston 69 into discharge 70,shown as broken off. The discharge of the spent waste or ash isessentially the same as in the previous embodiments and can be designedin the best way by persons skilled in the art.

In this embodiment, the waste stopper which is formed in pipe 53 and ispushed by piston 54 into the reaction chamber is heated, or better,pre-heated, in the upper section 56′ of the reaction chamber, viz. thesection of the reaction chamber which is provided with a tubular casing.Since that section of the reaction chamber is in contact with the gasoutlet conduit on one side and on the other side with the air chamber 63in which air is generally introduced at a temperature well above roomtemperature, e.g., about 100° C., the waste becomes heated andthermolysis begins even though no air is fed into that section of thereaction chamber. Therefore, even before air comes into contact with thewaste, it begins to undergo a thermolysis process. When it comes intocontact with the air, fed through the openings 62, the thermolysis ofcourse increases, and is completed in the layer of the waste that isclose to the air feed openings, the thickness, shape and borders ofwhich layer are variable. The air issuing from openings 62 passesthrough the waste in a cross-sectional direction, forms partialcombustion gases in the thermolysis zone and then completes thegasification in the gasification zone, which is the portion of thereaction chamber section 56″ that is interposed between the thermolysiszone and the orifices 55, from which issue the fuel gases produced. Theseparation between the thermolysis and the gasifications zones is notfixed and can vary with variations of the process parameters and withthe passage of time and therefore could not be marked in FIG. 8. Thefuel gases therefore issue from orifices 55 and from them flow throughgas settling chamber 64, conduit 65 and outlet 66. The progress of thewaste through the reaction chamber and the discharge of ashes occursmoothly and gradually.

It should be understood that in an apparatus according to the invention,if the reaction chamber is vertical, there should be some restriction init or some way of creating a resistance to the flow of the waste. In thepreceding embodiments that resistance is created by the lower conicalportion of the reaction chamber. In the embodiment of FIG. 8 it iscreated by the very shape of the reaction chamber. It could have beenthought that in such a reaction chamber the waste would spill out on theuncovered part of the concave side and fill the space that is presentlyan air chamber 63 and occlude the orifices 62. It is surprising thatthis is not so. The initial heating in zone 56′ of the reaction chamberhas imparted to the waste a certain compactness, so that the wasteremains more or less in the shape indicated in the drawing. On theconcave side of the reaction chamber the waste may roll upon itself tosome extent, forming a kind of superficial vortices, but it remainsessentially in it general, regular shape and the formation of suchvortices is only an advantage because it improves the contact of the airwith the waste. The waste would not drop downwards by itself and if notsubject to impulses from the piston (which is piston number 54 in FIG.8), would remain unmoving. It is the combined and synchronized action ofthe various pistons that provides the smooth and substantiallycontinuous motion of the waste and of the ashes and renders theapparatus extremely efficient and productive.

The reaction chamber has been described as having an axis that is an arcof circle. It should be understood that, while this is the preferredshape, it is not an exclusive one, and the shape, curvature radius andother geometrical parameters of the reaction zone may be changed byskilled persons if desired to obtain a smooth progress of the treatedwaste. Generally, it is preferred the axis of the chamber should betangent to the vertical at its top and should subtend an arc close to 45degrees at its bottom, viz. at the level at which the gas outletorifices terminate, but these geometrical features are not compulsoryand can be adjusted by skilled persons to obtain optimal progress of thewaste.

It will be clear that, though the pistons have an alternating motion andthe waste is fed by portions, each portion being what was called a“stopper”, the operation of the apparatus is continuous for allpractical purposes, as the portions can be made small enough and thefrequency of the piston motion high enough, so that no overalldiscontinuity is felt. Additionally, as has been said, pistons 25 and 27or 52 and 54 can fragment and/or cut off parts which can disturb themovement of the waste in the apparatus, viz., it may be said, can act asguillotines. In this sense the method and apparatus of the invention aresaid to be continuous. Of course, they could be made absolutelycontinuous by using other waste driving apparatus, e.g. of the screwextruder type, and skilled persons could easily substitute suchapparatus for the one of the described embodiment.

In an example of application of the invention, an industrial apparatuswas built having dimensions 2×2×3 meters and heat output 1.0 MW. Theapparatus had a capacity of 1 ton/hr of waste, consisting of 35 wt % ofcombustible materials, 50 wt % of humidity and 15 wt % of incombustiblematerials. It produced a gas output of 2000 m³/hr, with a residue of 300kg/hr.

While embodiments of the invention have been described by way ofillustration, it will be understood that the invention may be carriedout with many modifications, variations and adaptations, withoutdeparting from its spirit or exceeding the scope of the claims.

1. Method of continuous treatment of domestic waste, which comprises: a)providing a reaction space; b) feeding the waste to be treated to saidreaction space at a controlled rate; c) concurrently compacting saidwaste to form a stopper preventing leakage of gases from said reactionspace; d) feeding an oxygen-containing gas to said reaction space,whereby to affect the combustion of said waste and produce gases andsolid material; e) controlling the temperature in the reaction space byactivating means for controlling the temperature of saidoxygen-containing gas; f) causing said oxygen-containing gas to passthrough said solid material, thereby causing said oxygen-containing gasto react with said solid material, whereby to produce fuel gases andash; wherein, the composition and quality of said fuel gases arecontrolled by determining the desired equilibrium constant of thereaction of said oxygen-containing gas with said solid material andmaintaining said desired equilibrium constant by controlling thetemperature in the reaction space and the ratio of the waste to theoxygen-containing gas, which ratio is controlled by controlling therates of feeding said waste and said oxygen-containing gas to saidreaction space; and wherein, the feeding of the waste is done byproviding two conduits, each comprising a piston at its end and disposedat right angles to each other and operating said pistons in asynchronized manner in which one of said pistons to carries out theforward stroke when the other of said pistons carries out its rearwardstroke and vice versa, thereby allowing continuous operation of saidapparatus.
 2. Method according to claim 1, wherein the reaction spaceincludes a thermolysis zone and a gasification zone and theoxygen-containing gas is fed to said thermolysis zone.
 3. Methodaccording to claim 2, wherein the thermolysis zone is superimposed tothe gasification zone.
 4. Method according to claim 2, wherein thereaction chamber has an arcuate shape and said the thermolysis zone islocated at the concavity of said arcuate shape.
 5. Method according toclaim 1, wherein the oxygen-containing gas is air.
 6. Method accordingto claim 1, wherein the fuels gases comprise carbon monoxide andhydrogen.
 7. Method according to claim 1, comprising advancing the wastethrough the reaction space in the form of an elongated mass, feedingoxygen containing gas to one side of said elongated mass and withdrawingfuel gases from the other side of said elongated mass.
 8. Methodaccording to claim 1, wherein the oxygen containing gas is fed at hightemperature and under pressure.
 9. Apparatus for the continuoustreatment of domestic waste, which is unsorted by size, said apparatuscomprising: (a) a reaction chamber; (b) means for feeding anoxygen-containing gas to said reaction chamber; (c) means forcontrolling the temperature of said oxygen-containing gas; (d) means forcontrolling the composition of said oxygen-containing gas; (e) a gasreceiving space for receiving the gases produced in the gasificationzone of said reaction chamber, provided with an outlet for said gases;(f) means for discharging the ash formed at the bottom of said reactionchamber; (g) a first conduit comprising a first piston at its endfurthest from said reaction chamber; (h) a second conduit disposed atright angles to said first conduit such that a junction is formed at theintersection of said first conduit with said second conduit, said secondconduit comprises a second piston at its first end and has its secondend located within said reaction chamber; (i) means for synchronizingthe motion of said first and said second pistons; and (j) a hopper, intowhich the waste to be processed is loaded and from which said waste isdischarged into said first conduit; wherein, said first and said secondpistons fragment and/or cut off parts which can disturb the movement ofthe waste in the apparatus and said synchronizing means comprise meansfor causing one of said pistons to carry out the forward stroke when theother of said pistons carries out its rearward stroke and vice versa,thereby allowing continuous operation of said apparatus.
 10. Apparatusaccording to claim 9, wherein the air chamber is situated above thereaction chamber.
 11. Apparatus according to claim 9, wherein the airchamber is situated on one side of the reaction chamber.
 12. Apparatusaccording to claim 9, wherein both waste conduits are horizontal. 13.Apparatus according to claim 9, wherein one of the waste conduits ishorizontal and the other is vertical.
 14. Apparatus according to claim9, further comprising or associated with means for feedingoxygen-containing gas under pressure to the reaction chamber. 15.Apparatus according to claim 9, wherein the means for discharging theash comprise a piston, a conduit for the ash advanced by the piston, andan outlet.
 16. Apparatus according to claim 9, wherein the means fordischarging the ash comprise: (a) a first conduit comprising a firstpiston; (b) a second conduit disposed at right angles to said firstconduit such that a junction is formed at the intersection of said firstconduit with said second conduit, said second conduit comprising asecond piston at its first end and having an outlet located at itssecond end; and (c) means for synchronizing the motion of said first andsaid second pistons; wherein, said synchronizing means comprise meansfor causing one of said pistons to carry out the forward stroke when theother of said pistons carries out its rearward stroke and vice versa,thereby allowing continuous discharging of ash from said apparatus. 17.Apparatus according to claim 9, wherein the reaction chamber iselongated and curved, having its concavity directed towards theoxygen-containing gas feed means and having its convexity directedtowards the gas receiving space.